(1) Field of the Invention
The present invention relates to a device and method for controlling an automatic transmission which perform a control of a gear shift ratio on a basis of an estimated value of a vehicle speed after a predetermined time.
(2) Description of Related Art Including Information Disclosed Under 37 C.F.R. §§1.97 and 1.98
A technique described in Japanese Patent Application Publication No. Heisei 9-21059 (this corresponds to a U.S. Pat. No. 5,857,937) and which uses a gear shift control using an estimated vehicle speed after a predetermined time is known, with an aim to prevent an occurrence of an engine racing or so forth at a time of a gear shift control due to a delay in a mechanical component during the gear shift control.
Another technique for determining a gear shift stage using a read-ahead vehicle speed is described in Japanese Patent Application Publication No. Heisei 11-325231. In an automatic gearbox, the gear shift stage is selected using the shift map in which generally ideal shift lines are set. The ideal shift lines serve to determine the gear shift lines on a basis of actual vehicle speed and an accelerator pedal opening angle. For example, in a case of a geared automatic transmission, in a region in which an accelerator pedal opening angle is large, a region of a low shaft stage is widely set to maintain the low gear shift stage. On the other hand, in a region in which the accelerator opening angle is small, respective regions of the shift stages are set to be narrowed to enable up-shifts in sequence.